html, body {
    background-color: #000;
    color: #eee;
    margin: 0px;
    padding: 0px;
    position: fixed;
    overflow: hidden;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;

    /* Prevent user selection. */
    user-select: none;
    touch-callout: none;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
}
.dialog {
    display: none;
    align-items: center;
    justify-content: center;
    font-family: sans-serif;
    font-size: 170%;
    position: absolute;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.2);
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
}
.dialog.visible {
    display: flex;
}
.dialog .wrap {
    padding: 30px 60px;
    margin: 20px auto;
    width: 60%;
    background: rgba(0, 0, 0, 0.8);
    border-radius: 5px;
}
.dialog h1 {
    margin: 0;
}

a, a:visited {
    color: skyblue;
}

#watermark img {
    position: fixed;
    overflow: hidden;
    left: 0;
    bottom: 0;
    opacity: 0.3;
    width: 24px;
    height: 24px;
    padding: 12px;
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
}
#watermark img:hover {
    opacity: 1;
    -webkit-filter: drop-shadow(white 0 0 5px);
}


canvas {
    cursor: -webkit-grab;
}
canvas:active {
    cursor: -webkit-grabbing;
}

#play-overlay {
    position: fixed;
    width: 100%;
    height: 100%;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    align-items: center;
    justify-content: center;
}
#play-overlay.visible {
    display: flex;
}
#play-overlay img {
    width: 30%;
    height: 30%;
}

#error .message {
    font-family: monospace;
}
